The present disclosure relates to a retardation film having optical anisotropy and a method of producing the same. The present disclousre also relates to a display device provided with the retardation film having optical anisotropy.
In related art, as a stereoscopic image display device of a type using polarizing glasses, there is a device that emits polarized light varying between pixels for the left eye and pixels for the right eye. Such a display device makes it possible for a viewer wearing the polarizing glasses to view a stereoscopic image, by causing light emitted from the pixels for the left eye to enter only the left eye and light emitted from the pixels for the right eye to enter only the right eye.
For example, in Japanese Patent No. 3360787, a retardation film is used to emit light in polarization varying between the pixels for the left eye and the pixels for the right eye. In this retardation film, a phase difference region having a slow axis or a fast axis in one direction is provided for the pixels for the left eye, and a phase difference region having a slow axis or a fast axis in a direction different from that of the above-mentioned phase difference region is provided for the pixels for the right eye.
Incidentally, when affixing the retardation film described above to a display surface of a display panel, it is necessary to align the phase difference regions with the pixels of the display panel. Generally, a glass substrate is used for both the retardation film and the display panel, and expansion and shrinkage of the retardation film and the display panel due to an external environment hardly occur. Therefore, when the retardation film and the display panel are produced so that the pitch of the phase difference region and the pitch of the pixel agree with each other beforehand, there is no possibility that misalignment between the phase difference regions and the pixels will occur.
However, when a resin film is used as a base of the retardation film, the resin film may expand or shrink due to an external environment. Thus, it is conceivable to use, as the base of the retardation film, a thermoplastic norbornene resin film with extremely high dimensional stability. However, there is such a problem that this resin film has low adhesion with other resins and thus is not suitable for the base of the retardation film.
In view of the foregoing, firstly, it is desirable to provide a retardation film using a thermoplastic norbornene resin film as a base, and a method of producing the same. Secondly, it is desirable to provide a display device with such a retardation film.